Signors to charles f



(No Model.)

H. E. WAITE & s. H. BARTLETT.

TELEPHONE EXCHANGE SYSTEM.

Patented July 22, 1884.

WITJKESSES To all whom, it may concern.-

NHED STATES 'ATENT 'EEreE.

HENRY E. WAITE AND sAMUEL H. BARTLETT, on NEW YORK, N. Y., A S-' SIGNORS T0 oHAELEs F. LivEEMoEE, TEUsTEE, or SAME rLAoE.

TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 302,364, dated July 22, 1884:.

Applicalioh tiled March 31, 1884. (No model).

Be it known that we, HENRY E. WAITE and SAMUEL H. BARTLETT, of the city, county, and State of New York, have invented a new and useful Improvement in TGIBPhOHB-EX- change Systems, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making part of this specification;

Our invention relates to the employment in a listening telephone system of an annuncia tor-drop which by its action breaks the normal circuit of the subscribers line, and automatically connects him with a telephone strapped to the ear of the listener at the central office, enabling the subscriber at once, and

without waiting for an answering signal, to

communicate with the central office, and to name the subscriber with whom he desires to be put in communication, after which thelistening operator answers, and calls at once to the board, annunciators, and subscribers line; and Fig. 2 shows one of the annunciators in side elevation, its connection with the terminal tube in the switch-table and with the ground, and the manner in which the annunciator'drop connects a subscribers line with the telephone of the listening operator.

A A A represent annunciators in the central oifice, connected each,when the annunciator-drop d is in its normal position, through a spring, 8, and conductor 2, with a terminal tube, f, in the switch-board S B, and thence through spring 8, rod 9', and conductor 3with the ground. The annunciator-frame is of metal and forms a part of the subscribers circuit, a conductor, 1 or 1, extending thence to the subscribers instrument or telephone, two of which are indicated at T and T, having each a transmitter, receiver R', magneto-call M, and local battery contained in a box, L B,

and grounded at G. The subscribers line is grounded normally through the annunciator comes in contact with a spring or bar, 8 connected by wire 4 with the transmitter T and receiver 1% of the listening operators telephone, and thence through battery B with the ground of the latter,,enabling the subscriber at once, and without waiting for an answering signal, to communicate his wishes to the central-office operator, who at once calls to the switch attendant, and the latter immediately restores the annunciator-drop of the calling subscriber to its original position, signals the subscriber called for, and connects the calling subscriber with the one called through the switch-board by means of plugs or pins 1) and 19, connected by a flexible conductor, 1), or in any other of the usual methods.- The two subscribers are thus placed in immediate communication over a single direct wire, which is cutout from any possibility of interruption from any other subscriber, and cannot be dis turbed except from the central office, where, if the attendant desires, he may signal either subscriber in any usual manner for the purpose of ascertaining whether they are still in communication or not. When the calling subscriber has completed his communication with the one called, he announces the fact to the central office listening operator by again, through hismagneto or local battery, operating the annunciator-drop, and, informing the listening operator of the fact, the latter causes the plugs to be withdrawn and the annunciator-drops to be restored to their original positions, and awaits other calls.

As above stated, the subscribers circuits are normally through the annunciator=drops, springs s, conductor 2, switch-board S B, eonductor 3, to ground G. After the annuncia tor-drop has fallen the circuit is through said drop, spring 8 and conductor 4, to the listening operators telephone, and thence to the ing a direct and unbroken connection between the two. The means for breaking the ground-connections of the terminal tubes with the centralofiice ground, upon the introduction of the plugs 19 and p in said tubes, may be such as is ordinarily employed for that purpose, being shown as consisting of a sliding headed pin, 0, the head 0 of which is normally held in contact with spring 8 by means of a spring, 0*, surrounding the pin a, and from the spring 8 a conductor, 8, extends to the ground. W'hen the plug 1) or p is forced into the terminal tube, overcoming the tension of the spring 0 the head 0 is removed from contact with spring 8, and the circuit will then be through the plug and its flexible conductor, as explained.

Ye are aware that it is not new, broadly, to break the normal ground of a subscriber at the central office and to cut in the listening operators telephone by the falling of an an nunciator-sluitter; but,

Having now described our invention, we claim as new In a telephone-exchange system, the combination, with the subscribers lines, grounded, each through an annunciator in the central ollice, ofannunciator-drops and contact-points arranged in relation to said drops substantially as described, whereby when a drop is operated by a subscribers line it is made to automatically connect said line with the list ening operators telephone, and when restored to its normal position and its line-terminal and annu-nciator are connected with the lineterminal and annunciator of another subscribers line, by a suitable connection uniting said terminals and breaking their central-officc ground-connections, a single, direct, and unbroken line or circuit is formed between said subscribers, substantially as described.

In testimony whereof we have hereunto set our hands this 27th day of March, A. D. 1884.

HENRY E. WAITE. SAMUEL H. BARTLETT.

Vitn esses:

CHARLES SPARMAN, 7M. H. TOODIIULL. 

